"There's intimidation. It's a world within a world - it has its own currency, it has its leaders, it has its intimidators, it has its good Samaritans. It's just a really scary place."

Gary revealed that his mother was one of the people who inspired him to turn his life around after a visit to him in prison.

His mother was the first person to visit Gary, two weeks after he had been sent to Mountjoy but she had injured her hip and had to be helped up to the prison.

"My brother Noel was linking her and bringing her in. And I just looked at her struggling in to see me.

"It was that very precise moment I said 'You absolute gobshite. This is it, you change your life for this woman or forget about it, it's not worth it'."

"That was the penny drop moment."

Gary decided in prison he wanted to change his life and impress his mother, saying "it's not the time you do Gary, it's what you're going to do with the time" and it was then he started writing.

He also spoke about how time in prison could become lonely, missing family and friends, and how at one point he was either going to go back to drugs or commit suicide until one friend in prison stepped in.

"He didn't wrap me up in cotton wool. He went through me for a shortcut.

"Whatever way he came in on top of me it really worked.

"What I didn't know he did was he went into the kitchen [where Gary worked in prison] and told every single solitary man what happened to me.

"They were my family in there and they rallied around and they were absolutely incredible."

Gary also highlighted the struggles that people go through when they leave prison and the difficulty in getting work and how he wanted to prove people do come out of prison wanting to make a better life.

"You do the time when you come out as well, Ryan, I tried to get a job and it was the hardest thing."